fix test cases on String Node
Merge branch 'ChocoButter-2Become1' of https://github.com/DynamoDS/Dynamo into ChocoButter-2Become1
Fix default value issue
Merge pull request #1450 from ke-yu/fix_defaultvalue

Fix default value issue
Merge pull request #1430 from Zhengzi/ChocoButter-2Become1

fix test cases on String Node
use element UniqueIds instead of ElementIds